The Search by Peptide allows users to locate complexes in the database using an epitope sequence, a specific protein, a specific virus, or a combination of these. In the Peptide Sequence box, users can enter complete or partial sequences of epitopes. Wild card characters '[]', 'X' and '()' can also be used in this field. See examples below:

CXNCTFWCV _ Specifies a search for a 9mer epitope, where the 2nd position can present any amino acid. The other positions must present specifically the one indicated amino acid, such as a C in the first position.

C[AGPVLIM]NCTFWC[DE] _ Specifies a search for a 9mer epitope, where the 2nd position can present any of the seven amino acids indicated between brackets, and the last position can present either a D or an E.

CVX(6)D _ Specifies a search for a 9mer epitope whose sequence initiates with "CV", presents any other amino acids between the 3rd and the 7th position. The number between parenthesis indicates the number of repetitions of the amino acid indicated right before, in this case, "X".